.TH LIBPFM 3  "September, 2009" "" "Linux Programmer's Manual"
.SH NAME
pfm_get_event_next \- iterate over events
.SH SYNOPSIS
.nf
.B #include <perfmon/pfmlib.h>
.sp
.BI "int pfm_get_event_next(int "idx ");"
.sp
.SH DESCRIPTION
Events are uniquely identified with opaque integer identifiers.
There is no guaranteed order within identifiers. Thus, to list 
all the events, it is necessary to use iterators.

Events are grouped in tables within the libary. A table usually
corresponds to a PMU model or family. The library contains support
for multiple PMU models, thus it has multiple tables. Based on the
host hardware and software environments, tables get activated when
the library is initialized via \fBpfm_initialize()\fR. Events from
activated tables are called active events. Events from
non-activated tables are called supported events.

Event identifiers are usually retrieved via \fBpfm_find_event()\fR or
when encoding events.

To iterate over a list of events for a given PMU model, all that is
needed is an initial identifier for the PMU. The first event identifier
is usually obainted via \fBpfm_get_pmu_info()\fR.

The \fBpfm_get_event_next()\fR function returns the identifier of
next supported event after the one passed in \fBidx\fR. This iterator
stops when the last event for the PMU is passed as argument, in which
case the function returns -1.
.sp
.nf
void list_pmu_events(pfm_pmu_t pmu)
{
   struct pfm_event_info info;
   struct pfm_pmu_info pinfo;
   int i, ret;

   memset(&info, 0, sizeof(info));
   memset(&pinfo, 0, sizeof(pinfo));

   info.size = sizeof(info);
   pinfo.size = sizeof(pinfo);

   ret = pfm_get_pmu_info(pmu, &pinfo);
   if (ret != PFM_SUCCESS)
      errx(1, "cannot get pmu info");

   for (i = pinfo.first_event; i != -1; i = pfm_get_event_next(i)) {
      ret = pfm_get_event_info(i, &info);
      if (ret != PFM_SUCCESS)
        errx(1, "cannot get event info");

        printf("%s Event: %s::%s\\n",
               pinfo.present ? "Active" : "Supported",
               pinfo.name, info.name);
  }
}
.fi

.SH RETURN
The function returns the identifier of the next
supported event. It returns -1 when the argument is already the last
event for the PMU.

.SH ERRORS
No error code, besides -1, is returned by this function.
.SH SEE ALSO
pfm_find_event(3)
.SH AUTHOR
Stephane Eranian <eranian@gmail.com>
.PP
